There is also confusion in the US over whether the Federal
Reserve wants to raise rates or keep them low in the future
and concerns that a rebound in China is fading fast into the
second half of the year.

Nobody can accurately predict which way these events will go and
they will have a profound effect on the economy.

Here is Barclays (emphasis ours):

The global outlook has become increasingly
binary: not only could the outcome of next week’s UK
referendum significantly affect developments in Europe and
beyond, but this week’s FOMC communication made Fed policy also
feel increasingly bi-modal in the face of recent uncertainty
about the US labor market.

In a similar vein, this week’s Chinese data suggest that the
stimulus-driven growth rebound may already be starting to fade.
The political risks from the UK referendum could, thus,
usher in a global macro scenario much worse than our current
baseline.

So the global economic future could be as hard to predict as a
coin flip.

Here is what the probability of a Brexit looks like according to
Barclays:

Barclays

And here is what leaving the EU could do to global
international investment:

Barclays

Barclays said a Brexit would be particularly bad for the
Euro area, with the outcome halting decent growth
prospects:

We have raised slightly our baseline macroeconomic scenario
as fixed investment is finally picking up: we expect Euro area
GDP growth of 1.7% in 2016 and 1.8% in 2017.

However, under a “Leave” scenario, our growth forecast
falls significantly to 1.4% in 2016 and 0.4% in 2017, versus 1.7%
and 1.8% in a “Remain” outcome, respectively.

Some people, such as Mohamed El-Erian, the former CEO of the
Pacific Investment Management Co. (PIMCO) and current chief
economic adviser to Allianz,
saw this binary economy coming.

Back in March he predicted that the global economy
would hit a "T-junction" within three years.

Policymakers will either watch helplessly as the world sinks into
a mire of financial volatility and political collapse, or they
will find a way to unlock the piles of corporate cash sitting on
the sidelines, reinvigorating growth.

"The road we're on is coming to an end," El-Erian told reporters
in London earlier this year.